Question

MLAG setup - looks like hitting a L2 loop

  • 29 July 2019
  • 1 reply
  • 126 views

Hello,

We tried to set up a MLAG between 2 x670 switches and once we enabled the second "leg" (port 41 on sw1) looks like we did hit a loop. Unfortunately it's a production network and we are very limited in opportunities to reproduce it.

MLAG related configs are as follows:

sw1:
code:
create mlag peer "sw2" 
configure mlag peer "sw2" ipaddress 192.168.128.242 vr VR-Default
enable mlag port 41 peer "sw2" id 202
enable sharing 41 grouping 41-48 algorithm address-based L2 lacp




sw2:
code:
create mlag peer "sw1" 
configure mlag peer "sw1" ipaddress 192.168.128.241 vr VR-Default
enable mlag port 41 peer "sw1" id 202
enable sharing 41 grouping 37-48 algorithm address-based L2 lacp





MLAG peers see each other, checkpoint status is 'Up'. What caught my attention is this. On sw1:

code:
sw1.118 # debug hal show vsm 

VSM Blocking Filters:
Ingress port: 1:1
Blocked ports:
Unit 1 (inst 1 Fid A553 l3_inst 1 l3_Fid A551 l3rem_inst 1 l3rem_Fid A552 pend 0):
41 42 43 44 45 46 47 48

VSM Redirection: (Enabled)




But on sw2:

code:
sw2.29 # debug hal show vsm 

VSM Blocking Filters:
Ingress port: 1:1
Blocked ports:

VSM Redirection: (Enabled)




Could this be the cause of the problem (that there're no blocked ports for the filter)? If so, why they could've not been added?

Both switches are running 16.2.4.5-patch1-6.

1 reply

Userlevel 3
What does "show mlag peer" and "show mlag port" on both switches show?

Can you draw a network map of what you're trying to accomplish?

You created LAGs using ports 41-48 on one switch, and 37-48 on the other. Are you sure that is correct?

BTW 16.2 is end of service life in December. You should consider upgrading.

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